Gas-tight sealing device for rotary piston engines



Nov. Z2, 1966 HlRosHl TADo GAS-TIGHT SEALING DEVICE FOR ROTARY PISTON ENGINES Filed March 2, 1966 2/ i Jr i :wem-@R /1'1' rubi T/afa ATTORNEYS United States Patent O 3,286,912 GAS-TIGHT SEALING DEVICE FOR ROTARY PISTON ENGINES Hiroshi Tado, Snita-shi, Japan, assigner to YannarDiesel Engine Co., Ltd., Osaka, Japan, a corporation of Ja an P Filed Mar. 2, 1966, Ser. No. 531,251 Claims priority, application Japan, Mar. 11, 1965, 40/ 18,652 1 Claim. (Cl. 23o-145) The present invention relates to a rotary pist-on engine having a ycasing consisting of a central housing and side housings disposed on opposite sides thereof, a rotary shaft extending through the center of the central housing, and a rotary piston of -multi-cornered structure rotatably supported on an eccentric portion of the rotary shaft, and more particularly to a device for sealing gastight the angular portions or corners of the rotary piston in its axial direction.

In the rotary piston engine ofthe type described, spaces dened by the rotary piston and the inside face of the casing, that is, the inside faces of the 1central housing and the side housings form the operating chambers in which suction, compression, expansion and exhaust strokes are repeated as the rotary piston rotates. The abovedescribed gastight sealing device comprises an axial ygroove provided at each corner of the rotary piston and an apex sealing means provided in each groove. The iapex sealing means acts to separate the adjacent operating chambers from each other and to maintain a gastight seal between the adjacent operating chambers by being pressed against the inside face of the central housing by the pressure exterted on its bottom yface from the operating chamber Iat higher pressure.

During operation of the rotary piston engine, impact is generated between the 'apex sealing means `and the central housing due to machining errors and thermal deformation of the central housing land the sealing means, and static as well as dynamic variations and errors in the power transmission means for the rotary piston supporting the sealing means. This impact causes vibration, which in association with the sliding movement of the sealing means causes a periodic Ichange in the contact pressure between the faces, yand a resultant periodic change in the wear of the inside face of the central housing causes the so-called wavy wear of the inside face of the housing which is in sliding contact with the sealing means.

The primary object of the present invention is to provide an improvement in the sealing device of the type having -an `apex sealing means composed of an apex sealing member of thin-walled structure in order to relieve the impact as described above land a support block for the apex sealing member. According to the invention, the support block supporting the -apex sealing member is split into three `sections in order to minimize ygas leakage that may take place through 4a gap between the inside faces of the side housings and the raxial side faces of the apex sealing means when the engine is operating at low speed or when the axial side faces of the apex sealing means are caused to wear after operation over a long period of time. The sealing device of the invention is so arranged that the apex sealing member is supported solely by the central support block while the side blocks on opposite sides of the central block contact the latter with their slant faces and are urged radially outwardly by a spring disposed in the bottom of the above-described axial groove so that the side blocks can be urged axially outwardly by the reaction force caused by the abovedescribed slant faces to completely seal the gap between the sealing means and the inside faces of the side housings. In this manner, the sealing action by the apex 3,286,912 Patented Nov. 2.2, 1966 ice sealing means at its axial side faces can be completely effected and thus any lowering of engine output due to gas leakage can be prevented. In other words, the important feature of the present invention resides in that the apex sealing function (for peripheral sealing) and the side sealing function (for axial sealing) of the apex sealing means are shared by the apex sealing lmembers and the side blocks respectively, and thus the block divided into three sections by the slant faces can Iatt-ain the respective sealing functions.

It is needless to say as described above that, during operation of the engine, gas pressure from the operating chamber at higher pressure is exerted on the bottom faces of the blocks in yaddition to the force exerted by the abovedescribed spring.

Preferred embodiments of the present invention will hereunder 'be described with reference to the accompanyin drawings in which:

FIG. 1 is a front elevational View of a corner portion of a rotary piston of a rotary piston engine, illustrating -an embodiment of the apex sealing means :according to the present invention; l

FIG. 2 is la section taken on line II-II in FIG. 1;

FIG. 3 is a view similar to FIG. 1, but illustrating another embodiment of the invention; and

FIG. 4 is a section taken on the line IV--IV in FIG. 3.

FIGS. 1 and 2 illustrate one embodiment according to the invention. In FIG. 1, a groove 5 is provided in an angular or corner portion of a rotary piston 3 rotating in la direction of -arrow within a central housing 1. The groove extends in the axial direction of the rotary piston 3 and contains therein an yapex sealing member 7 and a support block. The support block is yaxially split into three sub-blocks, that is side sub-blocks 31 and `a central sub-block 33 at slant faces 9 as shown in FIG. 2. The side sub-blocks 31 are urged 'by an apex sealing spring 11 so as to be pressed against the central sub-block 31 from below and at the same time to be surged sidewards to make pressure contact with side housings 17 to eiect the side sealing action.

Corner sealing members 13 .and side sealing members 19 are provided on opposite sides of the rotary piston 3 to effect gastight lsealing between the rotary piston 3 and the Side housings 17. Reference numeral 15 resignates a corner sealing spring which urges each corner sealing member 13 towards the side housing 17.

The apex sealing member 7 is supported by the central support sub-block 33 by being brought into contact at its root portion with a cut-out portion of the central subblock 33. The apex sealing spring 11 disposed |between the 'bottom of the support block assembly and the axial -groove 5 of the rotary piston 3 urges the side support subblocks 31 radially outwardly, so that the side sub-blocks 31 support t-he central support sub-block 33 thereon and at the same time urge the apex sealing member 7 through the central support sub-block 33 ont-o the inside face of the central housing 1 for sliding contact therewith. A space 35 is provided between the bottom of the cut-out of each side sub-block 31 and the lower end of the yapex sealing member 7, lest the side sub-blocks 31 -should directly contact the apex sealing member 7 to urge the latter radi-ally outwardly. A cavity 10 having an open lower end is provided in the centr-al support sub-block 33 as a common technical means of reducing the weight of the block and for thereby minimizing the force of impact.

Another embodiment of the invention will next be described wit-h reference to FIGS. 3 and 4.

The sealing means in this embodiment is provided Wit-h an apex sealing member 7 which is composed of two sections of line symmetry. The apex sealing member 7 has an arcuate top end and is fitted in an axial groove 5 in the rotary piston 3 and in an inverted U-shape by being tions of a central support sub-block 33k and by being sup` ported thereby. The apex sealingV member 7 may -be formed -as ia unitary body of inverted U-shape. i

The upper end of the central support sub-.block 33 is slightly spaced by a` gap 31 from the apex sealing member 7 of thin-walled structure. The gap 21 is such that the apex sealing member 7 may not abut the central sub-block 33 even when it is defiected due to impact. It will be understood that this gap 21 serves to suciently maintain the shock absorbing action .and to preventY gas leakage by virtue 'of its labyrinth effect. A plurality lof axial recesses `41 are provided at the upper end of the central support sub-'block 33, and a communication passage'45 extends through the central sub-block; 33 in the radial direction of the rotary piston 3 in order to balance gas pressures in the spaces above the upper end of the apex sealing member V7. This is in yorder to lprevent blow-through of gas which may 'be caused by deformation of the `apex sealing member 7 due to gas pressure at the upper end of lthe central subblock 33. Near opposite axial ends ofthe groove 5, side sub-blocks 31 are disposed in a manner to be freely axially movable between the apex sealing member 7 :and they groove 5.` Any further explanation will 'be omitted since this embodimentis similar to the previous embodiment except `for the points described above.

In a conventional'apex sealing means having a support block4 of unitary structure, side gaps are progressively enlarged to cause increased'gas leakage therethrough as Vthe support iblock gradually `wears in its axial direction. In the inventive apex sealing means, however, the side `.support sub-blocks are always urged into intimate contact with the inside faces of the side housings by the action of the `apex sealing spring and the slant faces as described above and act to take the greater portion of the-gastight sealing action of the apex sealing means in its axial direction, with the result thatany Wear that may take place in the side sub-'blocks vdoes not bring forth an increase in the side gaps. Therefore, the inventive apex sealing means shows an improved gastight sealing action during operation of the engine atlow speed and after operation housing, and a Yrotary piston of multicornered structure.,

rotatably supportedilon lan eccentric portion of said VVrotary shaft, for the purpose of sealing gastight the corner portions of said rotary piston in its axial direction, said device comprising apex sealing means including an axial groove provided in the corner portion of said rotary piston, an

apex sealing member of thin-Walled structure disposed in said groove and having a suitably curved top end, a support block for supporting said apex ysealing member in said groove,v said support block being axially split into three sections tlo form a central sub-block and side sublblocks, on opposite sides of said central sub-block which contactwith each other at theirslant faces, said central sub-block supporting said apex sealing kmember thereon, and a spring disposed yat the-'bottom of said kgroove for urging the lower ends of said side sub-blocks radially outwardly of said rotary piston.

References Cited by the Examinerl UNITED STATES PATENTS 723,656 3/1903 Dunnl 91-141 v 3,103,920 9/1963 Georges 123-8 3,127,095 3/1964 Froede 123--8 y3,130,900 4/ 1964 Schlor i 23,0-145 3,176,909 4/1965l Maurhoi 230-145 3,251,541 5/ 1966 Paschke 230`145 MARK NEWMAN, Primary Examiner.

W. J. GOODLIN, Assistant Examiner. 

